Introduction: Depression is a common disorder that is often associated with other mental and physical disorders. One of the innovative approaches applied in depressed patients is transcranial direct current stimulation. Objective: The aim of this study is to determine the effectiveness of transcranial direct electrical stimulations on reducing the severity of depression and negative automatic thoughts. Method: This study is a quasi-experimental study. The population of it all depressed women formed in Tehran in 2015-16. A total of 24 subjects were selected by convenience sampling and randomly assigned into two test (n=12) and control (n=12) groups. The assessment tool used in the clinical interview was Beck Depression Inventory (BDI- Form 21) and automatic thoughts questionnaire (ATQ) respectively. The treatment sessions with a transcranial direct current stimulation (tDCS) included 15-20 min anodal stimulation of T3 region, and Kathodal stimulation of FD1 with a current of 2 mA. Data were analyzed using analysis of covariance and a dependent t-test. Results: Analysis of the data using analysis of covariance showed that there is a significant difference between tDCS and control groups in the rates of depression (p<0.05). There was also a significant difference between tDCS and control groups in terms of belief and the frequency of automatic thoughts (p<0.05). Conclusion: According to the results, it seems that transcranial direct current stimulation can reduce the severity of depression. Therefore, psychologists and psychotherapists can use it as a method of intervention used to improve symptoms in patients with depression.